Means and method of straightening well bores



Aug. 28, 1934.

MEANS AND METHOD OF STRAIGHTENING WELL BORES M. G. EARLE'Y ,Filed June 25, 1951 5 Sheets-Sheet l Mqye G arle] INVENTOR.

miauw@ A A TTORNEYS.

Allg. 28, 1934; y M G. EARLEY 1,971,480

MEANS AND METHOD OF STRAIGHTENING WELL BORES Filed June 25 1951 3 Sheets-Sheet 2 INVENTOR.

ATTORNEYS.

Aug. 28, 1934. M. G. EARLEY MEANS ANDl METHOD OF STRAIGHTENINGWELL BORES Filed June 25 1931 '3 Sheets-Sheet 3 UNITED STATES PATENT OFFICE MEANS AND METHOD OF STRAIGHTENING WELL BORES Moye G. Earley, Houston, Tex., assignor to J. S. Abercrombie Company, a corporation Application June 25, 1931, Serial No. 546,766

10 Claims. (Cl. Z55-1) The invention relates to an improvement in more nearly vertical direction by utilizing a spemeans and method of straightening or correcting cial type of drill stem coupling. the direction of Well bores. Another object of the invention is to provide In the drilling of wells it is the rule rather than a method of straightening well bores by posi- ,1 the exception that the well bore is quite crooked, tioning the drill in the crooked bore at an incli- 60 in the majority of cases and deviates from the nation toward the vertical and continuing the vertical a considerable distance. In fact, it is not drilling of the well bore. uncommon for a Well to be deflected from one to It is also an object of the invention to correct five or six degrees which will cause considerable the inclination of the well bore by tilting the bit lateral deviationfrom the vertical when the depth to a position between the vertical and the incli- 65A of the well is considered. In many instances nation of the well bore with respect to the verwells have been drilled wherein the bottom of tical and continuing the drilling of the bore with the well bore was offset a distance of several hunthe bit thus positioned until the direction of th dred feet from the top and its general contour bore returns to vertical.

quite crooked.` When the operator realizes that Other and further objects of the invention will 70 his Well is crooked it is then necessary to plug be readily apparent when the following descripup the well bore to an elevation where the bore tion is considered in connection with the accomis straight and to then recommence drilling in panying drawings wherein the 4hope that the second start will result in a Fig. 1 is a central vertical section of one type 2o straight hole. In many instances where the bit" of coupling which may be used in practicing the 75 vpasses from one formation to another it strikes invention, the section having been taken on the the second formation along a plane of cleavage line 1-1 of Fig. 2.

or strikes a boulder or other obstruction and the Fig. 2 is a central vertical section taken on the bit will be deflected from its normal vertical poline 2--2 of Fig. 1.

sition. The plugging back of the well and re- Fig. 3 is a diagrammatic view of the mecha- 80 drilling, gives no assurance that a straight hole nism used in practicing the invention and illuswill be obtained on the second attempt and in trating the positioning of the same in a crooked fact it often occurs that the bore will have to Well bore. be plugged as many as three or four times before Fig. 4 is a sectional view of another form of a comparatively straight hole is obtained. The coupling which may beused and is a view taken 85 present invention contemplatesv the provision of on the line 4-4 of Fig. 5.

a means and method for straightening or correct- Fig. 5 is a central horizontal section taken on ing the b'ore as soon as any deviation is observed the line 5--5A of Fig. 4. 'and eliminates the inconvenience and cost or Fig. 6 is a diagrammatic view of the invention. '3'5 plugging the well and re-drilling the same. Fig. 'l is another diagrammatic showing of the 90 It is one of the objects of the invention to proinvention using a full bore bit. vide a drill stem coupling of special construction Fig. 8 is a schematic showing of the successive which will permit an offset in the drill stem corrections of tbe well bore. which will cause the drill bit to be positioned at Fig. 9 is a section of a modification of the in- 40' an inclination with respect to the vdrill pipe. vention showing a reamer on the drill bit. 95

Another object of the invention is to provide In the rotary method of drilling wells the drill a coupling in the drill pipe which will buckle bit is connected to a string of drill pipe and when weight is placed thereon so that the drill bit rotation of the bit accomplished by rotation of r will be moved to a position which is inclined with the string of pipe. When, the drill bit strikes an 4** respect to the bore in which it is located. obstruction it is often deflected. Sometimes the Another object of the invention is to provide a deection is caused by permitting too great a drill stem coupling which will allow the drill bit weight on the string of pipe so that the drill I to follow the contour of the well bore when being pipe is flexed and in this manner deflects the bit.

Op lowered into or removed from the well but which Regardless of the cause of the deflection the vwill permit an offset relationship of the bit with crooked well bore which results is objectionable respect to the remainder of the drill pipe when as it not only offsets the location of the bottom Weight iS placed 1113011 the COlilJlngof the well but also makes it inconvenient for A still further object of the invention is to concontinued drilling due to flexure necessary in the tinue the drilling of a crooked well bore ln a drill pipe and also increases the cost of operallo tion of the well if it is to be pumped at al later date.

In order that the invention may be understood reference may be had to Fig. 3 where the straight or vertical portion of the bore is indicated at 2.

' This well bore may be any length but a deection in the bore is indicated as occurring at 4 and from thereon the bore isv inclined with respect hole, the drill bit indicated generally at 5, will be connected to a section of pipe or drill collar 6 whose length may be varied in accordance with conditions which will be later described. Above this section of pipe will be the improved coupling 7, which constitutes one ofthe elements of this invention. This coupling will be of such con struction that it will flex when weight is placed on the drill stem and cause the coupling to assume the-inclined position shown in Fig. 3. Above this couplingwill be a section 8 of drill pipe which will preferably be stiff and rigid. Above this section 8 will be the'standard` sections of' drill pipe 9 which continue to the surface.

When this device is lowered into the well bore the bit, of course, penetrates the bore ilrst and will hang in a vertical position from the drill pipe 9, while th'e bit is being loweredv through the vertical position 2 of the well bore. As the drill bit, however, is lowered into the inclined portion of the well and passes the point of deflection l0, the drill will come in contact with the lowermost wall 11 of the inclined b re, due to the provision of the coupling or connec ion 'l as the bit is lowered it will assume a position substantially parallel to the inclined lower surface 11 of the inclined portion oi' the bore.

The lowering of the bit is then continued until the bit 5 comes intoA engagement with the bottom l 13 of the well bore. When this positioning occurs the parts will be in the same position as shown in Fig. 3, except that the top 14 of the section 6 will be reclining against the well 1l of the bore. At thispoint, however, the weight of at least part of the drill pipe 9 is lowered onto the drill bit and when this weight is received by the coupling 7, this coupling is of such construction that it will assume the inclined position shown in Fig. 3 and the top of the coupling, dueto the stiffness of the` section 8 and the drill pipe 9, will remain against the side 11 of the inclined bore. The bottom of the coupling, however, will flex under the weight which is applied thereto and inasmuch as it is offset from the longitudinal axis of the drill pipe 9, and the section 8, due to its reclining position on the wall`11, it will obviously move to an offset position as far as possible. The amount of this offset movement will be limited either by the internal construction of the coupling or by the diameter of the wellbre and in the illustration shown in Fig. 3 the inclina- I tion or offset relationship has been limited by the wellbore where the top of the coupling contacts at 15 and the base of the coupling contacts on the opposite side of the'bore atA 16. It should be noted that the side of the bore 17 is 4what will be termed the high side, orY upper side of the well bore, whereas the side 11 will be .designated as the lower side.

-also rotate and impart ro -With the parts shown in the position of Fig. 3, the drill stem 9 is rotated from the surface. The coupling is of such construction that it will tation to the drin bi1; which is connected below the coupling. In this manner drilling of the well is continued with the bit in the position shown in Fig. 3 so that the continuation of the well bore indicated at 20 will be at an inclination more nearly toward the vertical than is the inclination of the well bore 4. It is to be understood that the bit 5, as seen in Fig. 3, may or may not be in a substantially vertical position. Its position at this time depends upon the degree of inclination of the bore with respect to the vertical, upon lthe diameterof the bore, the diameter of the bit, and upon the limiting movement of the coupling 7. `As an example, however, suppose that the inclination of the bore below the point 10 were 6 from vertical, and the construction of the coupling 7 were such that it would permit an inclination of 3 of the drill bit with respect to the longitudinal axis of the drill pipe 9. Itis then apparent that-when the parts are positioned as shown in Fig. 3, the drill bit would still be positioned 3 from vertical, and that a correction of 3 would have been made. The' gradual correction of the'bore is desirable in order that a sharp bend or change in direction of the well bore will not occur. The bore 20 continuing from the point 413 would therefore have Yto be drilled at an angle of but 3 with respect as in Fig. 3. For purposes of-illustration this an-Y gle of inclination with respect to the vertical is `indi'cat'ed by the lines 101 and 102, which show that theinclination is at an angle of 12 from the vertical. It is now the problem of the operator to make a correction of 12 in order to restore the direction o f the well bore to vertical. It is desirable to make this correction gradually rather than to make it abruptlyv in a short distance. With this in mind, therefore, a correction of 3 will first be made by drilling the section indicated at 103 land as shown by the lines 1 04 and 105 the correction is 3. This 4correction is accomplished in a manner such as previously described in connection with Fig. 3. However, if a. pilot bit or bit of less diameter than the well bore is used the hole 20 shown in Fig. 3 will be drilled a distance substantially equal to the distance from the lower A edge 12 of the drill bit up to the. coupling 7 or the lowermost coupling 80. such as seen in Fig. 6. When this pilot hole 20 has been drilled at a corrected angle of 3 the bit will then be removed from the well and a bit of standard gauge lowered into the well. This bit lowered at this time is preferably what is known as a diamond point bit or a bit having a pilot point thereon so that the operator will be sure that this standard gauge bit will` follow the pilot hole 20 along the corrected inclination. This standard gauge bit is used to ream out the hole to bring it up to standard gauge the same as the straight hole 2 or the incline hole 4. As seen in Fig. 8, that portion 1030i the hole has been reamed out at the corrected in- .clination due to the use of lthe method and appaardgauge bit while practicing this invention it is desirable that the operator observe the distance which the bits pass into the well bore. Thus, if the operator insists that the length of the bit 5, the pipe 6 and the member 14 up to the coupling and the section 106-is drilled with the pilot bit, 5 on the-bottom 13 and begin drilling. He will, however, observe the distance that the drill bit passes into the hole so that he will know when the coupling approaches the shoulder 13 and inthis manner know that he has drilled the desired distance in making the correction. When the standard bit is then inserted, he will again observe the distance which is being reamed out and limit that distance to the'same as the depth of thepilot hole which has been drilled. In this manner the section 103, as seen in Fig. 8, is formed.

It is now desired to make a second correction of 3 and the pilot bit -is again lowered into the hole and the section 106 is drilled with the pilot bit, thus making a second correction of 3. 'I'he pilot bit is then removed and the standard gauge bit used to ream out the hole. This operation is repeated to form the section of hole 107 and again repeated to create the last portion 108 of the well bore. In this manner there have been four corrections of 3 each, so that the section 108 is vertical, the same as the section 2, but is offset there'- from a distance equal to the distance betweenA the center lines 109 and 110. The center line 109 represents that of the original vertical bore 2,`whereas the line 110 represents that of the corrected bore 108. It is to be understood that the inclination of the portion 4 and the portion 108 may be determined by acid'bottle measurements or by any other means.

When the section 108 has been completed the well bore is again vertical and the usual type of tool being employed in that formation may then be lowered into the well and the drilling continued. A

` The example given above is merely hypothetical and has been exaggerated intentionally in order that a complete understanding of the invention may be had. Under usual conditions the inclination would probably be very slight and the correction would be accordingly slight, but in event the deviation is considerablaas shown in the illustration, it is possible to restore the bore to a vertical position by practicing the invention as herein described.

In Fig. 7 a view of the invention is shown wherein the double couplings of Fig. 6 have been illustrated in combination with a full gauge 'bit 115. This illustration is-given order to indicate that the invention may be practiced by using a full gauge bit but when this is used the correction Which can be made will be less than if a pilot or smaller gauge bit is used. In the illustration of Fig. '7 the correction will be less due to the fact that the bit occupies the full diameter of the well bore and due to the fact the inclination of the bit with respect to the crooked hole will be less than if a pilot bit were used. Where the inclination or deviation of the well bore is slight it is quite possible that a full gauge bit may be. used in making the correction as seen in Fig. 7, using either the coupling 7 or the coupling 80 as desired.

The theory of the invention is based upon the forces which will be applied to the couplings 70 or and the buckling or flexing of the coupling is accomplished due to the fact that the lines of force are applied in the coupling in a manner such that the resultant of the horizontal and vertical components will give a resultant at an inclinatlon to the vertical component, and when the weight of the drill stem, 0r part of such weight, is applied to the coupling. When the drill bit rests on the bottom of the well bore, the coupling will be buckled or exed due to the fact that the contact of the bit with the well bore occurs at a position which is oiset from the vertical center line of the drill stem 8. It isto be understood that if the operations as described in connection with Fig. 8 were continued beyond the section 108 the well bore would again be inclined away from the vertical but in a direction opposite to that of the inclination of the section 4. It is, therefore, apparent that'when the driller is advised that he has made a sufficient number of corrections to have balanced the inclination of the section 4 that he will then cease operation with the couplings and replace his standard drill bit coupling directly on the drill stem.

While the invention has been shown and described as primarily directed to the restoring of the well bore to vertical, it is to be understood that it may be appliedy for other purposes such as inside tracking the well bore around junk in the hole. It often occurs that tools are lost in the hole and cannot be removed and a whip stock or other device is used to side track the bore away from the junk so that the drilling may proceed. If this is desired, this invention may be practiced without using the whip stock by merely.

plugging the well to a point above the junk and then attaching couplings in the drilll pipe and the bit will be directed at an incline with respect to the vertical bore. After suitable inclination has been obtained a full gauge bit may be used to continue the inclination a suiiicent distance so that the bore will be deflected to one side vof the junk.' In this manner the well can be drilled to any desired inclination from the vertical. After this distanceA has been accomplished the couplings will again be used to straighten up the bore to a vertical position so that the well bore will continue in a vertical direction but slightly offset from the original position. Applying this idea to Fig. 8 the junk would be located at about the elevation of the section 106 and the coupling could have been used throughout the side tracking operation, or, if desired, a straight bit could be used in drilling the section 103 so that it would have continued in the direction of the section 4 and after the proper deviation was accomplished the couplings would then again have been used to restore the vertical direction of the bore.

One form of the coupling 7 has been illustrated in Figs. 1 and 2 and comprises the housing 30, which is preferably made up of a cap 31and a base 32, which are threaded'intoengagement with each other at 33. Inside of the cap 31 is a connecting member 34, which is threaded at 35 to a section of pipe 36. This section may be thev section 8 illustrated in Fig. 3, or it may be a usual type of drill pipe. As show n' in Fig. 1,' however, this pipe 36 is threaded at 37 to receive the plug connection 38, which serves as a passage for a flow of ilushing fluid and is provided with the central opening 39. Connected to this plug 38 is a conduit 40, which extends substantially the length of the coupling 'l and receives a nipple 41 on the lower ends thereof. This nipple 41 is connected to the member 6, which may be the same as the section 6 shown in Fig. 3. Inside of this section is a; positioning ring 42, which receives the nipple 4l and a seal is maintained about this nipple by means of the stop the ring 42 the sealing around the nipple 41 may be adjusted. It is intended that the conduit may be of more or less flexible material so as to allow for the flexure or buckling of the coupling when the top of the drill bit is offset. With this arrangement a flow of fluid may be obtained through the coupling in order to maintain vthe usual circulation necessary in drilling by the rotary method.

In order that the lcoupling will transmit rota-- tion from the pipe 8 to the pipe 6, itis necessary A that drive members be provided, and the connecting member 34 is the uppermost element of this drive connection. This connecting memberis formed with the shoulder 45 which abuts against the contact ring 46 carried inside of the cap 31. This contact ring servesas a seal and transmits the thrust from the connecting member 34 to `the cap 3l, when the weight of thefdrill bit 'and portionsV below the connecting member are suspended. Below the shoulder 45 the connecting member 34 is formed with a ribbed construction 47 and' on the righthand side of Fig. 1, one of the ribs 48 is shown in section. On the lefthand side of Fig. 1 the section has been so illustrated that a channel 49 has been shown." This channel is disposed between two of the ribs 48. The lower end of the portion 47 is roundedl or beveled at 50 on the arc of a circle, and the ribs 48 are preferably tapered as shown at 51; The center part of this portion 47 is hollow, as at 52, and the conduit 40 passes axially through i the same.

A sleeve is provided inside of the housing 30 and is internally ribbed as at. 56 in order to re- Lribs'in co-engagement, asfbest seen in- Fig. 2.

Thus, if the connecting member 34 is rotated it will also impart rotation to the sleeve 55. Howj least equal to the taper between the the same as the shoulder the upper portion and is adapted to -in the upper end 69 of the lower connecting `member 70.

ever, the ribs 57 are tapered downwardly and outwardly so that the space between 'the ribs 57 andthe channels 49, and the ribs 48 and the channel 5 8 in the sleeve 55 gradually increases in. width and is of greater width at 59. The

vribs 56 terminate in an annular shoulder 60,

which is formed on an arc of a circle ,substantially the same as the circular arc on whichthe end 50 of the coupling 34 is formed. Thus a portion of a ball and socket connection is formedat this point which will larly in any-direction, a number 'of degrees at co-operating ribs on the parts. For purposes of illustration this coupling may be made up to permit an angular inclination of 3.

Thecenter of the sleeve 55 is provided with a Ipassage 61 so that the conduit 4 0 may extend therethrough. The lower portion 62 of the sleeve 55 is identical with the upper portionv previously described and is arranged to receive the upper end 63 of the drive bushing 64, which is formed with a ball seatat 65 to engage the lower shoulder 66 on the sleeve 55, which shoulder is 60. This drive bushing 64 is tapered at 67 ina manner similar to the taper of the ribs 48, so that a 3 tilting will be available at thispoint'also. This drive bushing 64 is symmetrical in its construction and the lower portion 68 is of the same arrangement as be received This upper end 69 of the connectallow the sleeve 55 to tilt angueither end of the sleeve55 and further descripv tion thereof is not believed to be necessary. The

arc of the circle on which ithe shoulder 65 is formed' has been indicated by the line'71.

The lower connecting' member 70 is formed with a shoulder 72 similar to the shoulder.45 on the upper connecting member and this member abuts on the lower contact ring 73 so that a thrust will be transmitted from the connecting member to the housing 7 'when the drill bit is suspended. This connecting member is reduced in size at 74 to pass through the opening 75 in the base 32 of the housing 7 and is threaded at 76 to receive the pipe 6.

From the 'foregoing construction it seems readily apparent that there are three 3 angular displacements provided inthe coupling so that the iinal resultant angular position of the pipe 6 with-respect to the pipe 36 will be an inclination of 3. The connecting' members inside of the housing are required, however, in order to carry the-thrust which will be applied to the coupling when the bit is to be rotated in the drilling operation. 'Ihis thrust will be transmitted from the connecting member 34 to thesleeve 55 to the drive bushing 64 and to the lower connecting member 70.A All of these parts intermesh with each other due to the rib and channel construction so thata positive drive will be assured even though angular displacement is possible.

Figs. 4 and 5 show a modified form of coupling which is indicated-at 80. This coupling contains the base 81 and the cap 82. This cap 82, however,- is connected directly to-the pipe 9 and is provided -with a hollow area 83 to allow for circulation of'fluid through the coupling. This cap 1 82 is provided with a rib construction 84, which,

as seen in Fig. 5, constitutesalternate ribs 85 and channel 86. -These ribs and channels are tapered outwardly and upwardly so that the drive bushing 88 disposed therein will `be rotated but,'

due to the tapered form of the ribs -89 on this drive bushing, limited be permitted between the two members and the thrust from thecap 82 to the drive bushing 88 will occur at the point 90, which is a portion of a ball and socket seat as described in connection with the'Fig. 1 coupling,

With this arrangement rotation will occur but tilting movement will be possible. The drive bushing 88 is disposed in the base 81 of the coupling and the shoulder ring 92 to carry the thrustwhen the lbit is suspended on the coupling. A packing 97 is provided above the shoulder 91 and is preferably of the type which will expand when subjected to fluid pressure so that it will form-a seal between the drive bushing'8'8 and the base 81 of the coupling. Thus the slight tilting movement of the drive bushing 88 with respect to the base of the coupling will not destroy the seal. If desired a packing 93 may bel vantage where the inclination of the well bore is slight and has continued for a considerable dis-A angular `displacement will 91 abuts against a contact.

ias

connect with the pipe 6 or other tance before it was discovered. Thus, the coupling 80 will be positioned above the section 8 of drill pipe and directly below this coupling 80 will be a second coupling, which is positioned away from the first coupling, however, a considerable distance. This connection. is byv means of the section of pipe 98 and this length of pipe may be' varied as the amount of angular displacement of the bit depends to some extent upon the length of this pipe 98 and the length of the pipe 6 connected to the bit 5. 1

It will be readily apparent that if the lower cou.- pling-SD were positioned, We will say, at a point 99 in the inclined bore the top of the bit 5 wouldthen be inclined with respect` to the bore at a greater degree than it would be if the parts were in the position shown in Fig. 6. The operation of this form of the invention is the same as in theFig. 3 embodiment.

Fig. 9 of the drawings shows an arrangement wherein the bit 5 has entered the pilot hole or corrected hole 20 and has drilled this hole fora considerable distance. This is the manner in which the pilot bit 5 of Figs. 3 and 6 will penetrate the formation. In Fig. 9, however, a slightly modied form of the apparatus is used in which the drill collar 6 is positioned as in the previous modication but the short section of pipe 6', as seen in Fig. 6, and the coupling 14 have been repositioned and connected directly to the drill collar 6, a reamer coupling 120. This coupling is preferably connected directly to the drill collar 6 in any suitablemanner and embodies a body portion 121, which is fitted with laterally directed reamer blades 122. These blades are integral with the body 121 or they may be removable and are preferably removable in order that they may bereplaced When worn. The blades here shown are of the two stage type so that the reaming operation is performed in two steps. As noted in Fig. 9

proceeds into the pilot hole the pilot holewill be With a structure reamed out to standard gauge. of this type it would be possible to modify somewhat the method as practiced in connection with Fig. 8 by merely making the drilling operation continuous'until such time as'the driller had reason to believe that the inclination of the well bore had been corrected to the desired direction. The driller could then remove the entire device including the reaming collar, the drill bit and the swivel coupling and run in an acid bottle or other device to determine the amount of correction which had been made.

As seen in Fig. 9, the section of pipe 6 of Fig. 6 has been elongated somewhat and would have attached to its upper end either one of the couplings 8'0 of Fig. 6 or a coupling s'uch as 7 in Fig. 3, so that the top of the drill bit and the reamer coupling would be offsetwith respect to the longitudinal axis of' the drill pipe. It is believed that the modification of Fig. 9 will be readily understood from ,the foregoing description and it .will be unnecessary to give any further illustration thereof in connection withthe coupling embodied in this invention.

The claims herein are limited to the method of operation, while the apparatus is claimed in my divisional copending application, Serial No. 728,- 54.3,f11ed June 1, 1934. L-

While specific forms of the coupling have 4been 'shown and described it is to be understood that the Y invention broadly contemplates a method of correcting the inclination of the well bore or changing its direction and that the in vention may be praclticed by devices other than those here illustrated so long as the method of tilting the top of the drill bit so thatthe bit assumes a position at an inclination with respect to the Well bore is utilized..

What I claim is:

1. A method of changing. the direction of inclined well bores including lowering a drill bit into the well bore so that'it will lie on the lower wall of the inclined bore, flexing the drill stem above the bit so. that the bit lis raised to a position inclined toward the vertical with respect to the inclination of the bore, and continuing the drilling of the well bore. 4

r2. A method of changing the direction of inclined well bores including lowering a drill bit into the well bore so that it ,will lie on the lower wall of the inclined bore, flexing the drill stem above the bit so that the bit is. raised to a position inclined toward the vertical with respect to the inclination of the bore, and continuing the drilling of the well bore until the bore has reached the vertical.

3. A method of changing the direction of inclined Well bores including lowering the drill bit to a position parallel to the inclined bore, changing the bit from such position to a more nearly vertical position, and continuing the drilling.

4. A method of changing the direction Aof ininto the inclined portion of the bore, positioning the bit nearer to the vertical than the inclination of the well bore is to the vertical, and drilling the bore with the bit so positioned.

l5. A method of correcting the inclination of well bores comprisingV lowering a drill bit into the well bore so that it will lie adjacent the lower side of the inclined portion of the bore with vits cutting edge on the bottom of the bore, tilting the top of the bit away from the lower side of the bore so that it assumes 'a more nearly vertical position, and rotating" the bit to continue the drilling of the well bore.

6. A methodof correcting the inclination of v well bores comprising lowering a drill bit into the well bore so that it will lie along, the lower side of the inclined portion of the bore -with its cutting edge on the bottom of the bore, moving the top of the bit away from the lower side of the bore so that the bit assumes a more nearly vertical position,v rotating the bit to continue the v drilling of the well bore in the corrected direction, and removing the drill bit after the bore has been corrected to the desired position.

7. A method of changing the inclination of well bores comprising positioning abit in the wellbore adjacentthe inclination of the bore and with its cutting edge on'the bottom of the bore, changing the top of the bit to a position as far as possible in the well bore in the desired direction, and continuing the drilling with'the bit thus changed so that the point of deviation of the bore will be changed.

8. A method of correcting the inclination ofwell bores and continuing the drilling of the bore in a vertical direction including tilting the 4drill bit in the inclined portion of the bore so that the cutting edge thereof contacts the bottom of the bore adjacent the uppermost edge ofthe bit and the top of the bit is adjacent the upper side of the bore, drilling the bore with the bit thus positioned.

9. A method of side tracking well bores including lowering a drm bit and drill stem into the well bore, lowering suflicient weight onto the bit t`o flex the drill stem so that the lbit is inclined with respect to the axis of the drill stem, and rotating the bit and stem when so positioned.

- 10. A method of side tracking well bores includ- 

